Gelled aqueous slurry explosive composition containing as a gas generating agent a carbonate or bicarbonate with a nitrite



A. A. ALBERT 3,390,032 GELLED AQUEOUS SLURRY EXPLOSIVE COMPOSITIONCONTAINING June 25, 1968 AS A GAS GENERATING AGENT A CARBONATE ORBICARBONATE WITH A NITRITE Filed Jan. 4, 1967 4.. 352 o m N. w m w m N o3 ov on on ow ow 92.:72 x :76 ON 7 6 ON om ow N :Lm m 5-6 om N om mm\w xz- 09 .N 09

O ASEHNB MOOHS ALFRED A. ALBERT ROBERT W. LAWRENCE INVENTORS.

ESMJ W AGENT United States Patent 3 390,032 GELLED AQUEOUS SEURRYEXPLOSIVE COMPO- SITION CONTAINING AS A GAS GENERATING AGENT A CARBONATEOR BICARBONATE WITH 3,39%332 Patented June 25, 1958 More specifically,the present invention is directed to an improved aeration agent foradjusting and improving the control of the specific gravity of a gelledaqueous slurry explosive composition at the time of blasting,

A NITRITE 5 wherein the improvement comprises a fast gas generatingAlfred A. eihert and Robert W. Lawrenc \ilg i g material of the groupconsisting of sodium bicarbonate, 3 asfilgnorstto g 'g Incorpomted!wflmmgtm potassium bicarbonate, sodium carbonate and potassium e acorpora ion 0 e aware i r v Ffled Jan. 1967, Set. N 607,261 carbonate,and mixtures the eof, ai id a slot gas gener a ing material of the groupconsisting of sodium nitrite,

3 Claims. (Cl. 149-45) 10 potassium nitrite, calcium nitrite and bariumnitiite, and

mixtures thereof.

ABSTRACT OF THE DISCLQSURE Examples of operation of the invention aregiven in parts by weight for aqueous slurry blasting agents with- Anexploslv? CPmPOSmOH COI,1tammg combmailon out and with metal fuelswherein it will be noted that tast and slow in situ gas generatingmaterials for ad ust- Example 1 contained no metal, Examples 2, 3 and 4com ing and llllpI'OVlllg the control of the spec fic gravity of tainedsilicon and Example 5 contained aluminum. These gelled aqueous slurfyexglqswe comppsltlon' Sodium examples are given in Table I and wereprepared as folcarbonate and sodium nitrite respectively, are such gaslows: generating materials.

(1) Make a solution by combining the AN, SN and water.

Heat to dissolve.

This invention relates to aeration agents and more par- Adlusi e P 10 ew en 5-4 and 6 With ammoticularly to an improved aeration agent foradjusting and hydroXlde f acetle field HSLIS Tequlred; u improving thecontrol of the specific gravity of a gelled Blend the Sodium a e, theSOdlllm Illlflte, aqueous slurry explosive composition at the time ofblastthe Coal: the E gums together Order and then ing. 0 blend With thesilicon or with the aluminum.

The advantages of incorporating aeration agents, for (4) With thesolution at a temperature of 140 F. mix specific gravity or densitycontrol, into aqueous slurry the dry ingredients into the solution.

TABLE I Example No 1 2 3 4 5 Components:

Silicon Type I (63% on 100 mesh) Silicon Ty Silicon Type 111 (all thru200 mesh).

Aluminum Flakes 5 Water 16.9 16.5 16. 5 16.5 16. 5 Ammonium Nitrate, pr53. 5 52. 0 52. O 52. 0 52.0 Sodium Nitrate, prills- 16.1 15. 6 15. 615. 6 15. 6 Ethylene Glycol 11. l 5.0 5. O 5. 0 5.0 Ground Coal 1. 2 1.2 1. 2 1.2 1. 2 Guar Gum 1 0.4 0. 4 0. 4 0.4 0.4 Guar Gum 2 0.8 0.8 0.80.8 0.8 Sodium Nitrite 0.025 0. 046 O. 046 0. 046 0. 045 SodiumBicarbonate 0. 025 0. 046 O. 046 0. G46 0. 046 Oxygen Balance, percent0. 8 -3. 4 -3. 4 -3. 4 -1.1 Final, 24 Hour Specific Gravity 1. 24 1.141.15 1.15 1.13 pH 5.0 4.8 5.2 4.7 5.0 Detonation Rate, M/S 5, 550 4, 6505, 250 5, (100 4, 750 Pipe Diameter, inches. 5 5 5 5 Booster XC-49 XC-49XC-49 XC-49 XC-49 Slurry Temperature, F 89 90 Underwater Measured EnergyWeight Basis,

Relative to Confined HP Gel:

Shock Energy 0.52 0.83 O. 84 0.78 0.73 Thrust Energy 0. 74 0.91 0.930.95 0.96

1 Natural guar gum. 2 Cross-linkable giiar gum. 3 Maximum specificgravitics 1.4-1.5.

explosives have been disclosed by Ferguson et al. (U.S. 3,288,658) andSwisstack (U.S. 3,288,661).

Now in accordance with the present invention an improved and uniquecombination of in situ gas generating chemicals has been discoveredwhich provides a rapidly obtained, but yet, reliably stable andefiicient specific gravity control. As disclosed in the aforementionedpatents, the control of specific gravity or density provides a means forenergy control of the explosive and in addition can be employed toimpart increased sensitivity, shock energy and thrust energy as will befurther demonstrated herein.

tzlsopsa search, Missouri, February 1961, vol. 1) and his collaboratorswith some minor modifications.

The data are reported relative to confined 60% HP gel. The charges, 201b. to 30 lb. in weight, are confined in 5-inch diameter by 28-inch longblack iron pipe. The pipes were suspended vertically, 12 feet below thesurface of the water to the charge center, and 3.8 feet from the bottomof the pond. The charges were initiated from the bottom with XC-49pentolite boosters (50/50 PETN/TNT), 3-inch diameter by t-inch hi h and190 grams in weight. The pressures generated by the detonations weresensed by piezoelectric hydrophone transducers and were recorded on anoscilloscope. The bubble times were also sensed by the transducers andwere recorded on the oscilloscope.

With reference to the examples, it will be noted that all compositionsshot with a high detonation rate. An outstanding result, however, wasthat the silicon compositions and particularly Si III gave thrust energyresults substantially equivalent to the aluminum and gave shock energyresults superior to that of the aluminum. This is shown graphically inthe attached drawing.

Another outstanding result was the ability of the aeration agent of thisinvention to develop a substantially constant specific gravity for theexlposive compositions immediately and over a sustained period of time.This is important, since under field conditions a charge may be firedsoon after placing in a bore hole or it may be fired a considerable timelater amounting to days. This, it is believed, is attributable to thefollowing. Addition of appropriate amounts of sodium bicarbonate andsodium nitrite to a slurry under reaction conditions produces gasesbelieved to be carbon dioxide and nitrogen. The former is producedrapidly giving an immediate lowering in density, while the latter isproduced slowly maintaining the desired low density as the carbondioxide is absorbed by the slurry. The density reduction is elficient(based on sodium nitrite), is reproducible. and stable. This rapidlyobtained density reduction is achieved without materially changing thecomposition of a slurry and can be varied easily and accurately.

This improved system of density control is applicabl to all slurry gelsproviding reaction conditions are present. The rate of both reactionsvary with pH and temperature. Acidity of the base slurry can be variedfrom the pH 3 to about pH 6. depending upon the rate of reaction desiredwith increased acidification accelerating the reaction and decreasedtemperature decelerating the reaction.

It will be appreciated that the ammonium cation in Equation I isordinarily introduced by the presence of ammonium nitrate. When,however, it is desired to entirely replace the ammonium nitrate withanother inorganic oxidizing salt or salts, such as, sodium nitrat orsodium perchlorate for example, it is necessary to incorporate acompound which is water soluble and contains nitrogen in the negativeoxidation state. Suitable compounds are those having the general formulaRNH where R is an acyl allranol or alkane group. Preferred compoundsinclude urea and sulfamic acid. wherein the former may be included as aportion of the carbonaceous fuel and the latter may be incorporated inan amount in the order of l to 1 molar ratio of acid [0 nitrite.

In Table 11, Examples 6 and 7 show compositions in parts by weight inwhich it will be noted in the subsummary that the combination of sodiumnitrite and sodium bicarbonate gave the best overall results. that is.the slurry neither continued to drop in density nor rose after timeclasped. These latter occurrences can be seen in the examples ofstraight sodium nitrite 1nd straight sodium bicarbonate respectively.

TABLE II Example No 6 7 Components:

Water 16. 5 16. 5 16. 9 16.0 10. 9 .lmmonium Nitrate (prills) 52.0 52. 053. 5 53. 5 53. 5 sodium Nitrate (coarse) 15.6 15. G 16.1 16. 1 16.1.llurninurn Flakes 8. 5 8. 5 Ethylene Glycol 5.0 5.0 11.1 11.1 11. 1llround Coal 1. 2 1.2 1. 2 1. 2 1. 2 Natural Guar Gum 1. 2 1. 2 1. 2 1.2 1. 2 Cross-linking Agent 0.0 0.03 0.03 0.2 0. 2 Sodium Nitrite 0. 000.045 0.045 0.09 Sodium Bicarbonate 0.045 0!) 0.045 .Fumarlc Acid 0. 1O. 055 0. l6 0. 20 0. 03 initial Temp, F 140 140 150 110 110 Final pH 3.3 4. 4 3. 6 3. O 4. 5

Sub-Summary Example 6 Maximum "Specific Gravity 1. 54 1. 54 PercentSodium Nitrite 0. 045 Percent Sodium Bicarbonate 0. 015 lpecific GravityAfter 2 Min.-- 1. 29 Specific Gravity After 72 Hours 1. 05 1. 23

Sub-Summary Example 7 Maximum Specific Gravity Percent sodium NitritePercent sodium Bicarbonate. lipecific Gravity aftor Cl Min Min 1J0 Hrsr42 Hrs 1. 41

l 4-1 hrs lit is evident that there are several factors which willinfluence conditions for the most satisfactory operation of theinvention. For example, the method of introduction of the reactingchemicals forming the aeration agent of this invention may be in theform of particulate dry solids, solutions or suspensions. Thesechemicals as a solution, suspension or dry may be added to the slurry asmixed, or a solution or suspension thereof may be inlected into thegravity flow of the slurry after mixing, or a solution or suspensionthereof may be injected into the pumped fiow conduit of the slurry aftermixing and pumping. in all these variations, the aerated product may bedirectly charged into packages where desired or directly pumped into abore-hole.

Moreover, the present invention contemplates as the aeration agent theutilization of fast gas generating material of the group consisting ofsodium bicarbonate, potassium bicarbonate, sodium carbonate, andpotassium carbonate, and mixtures thereof and slow gas generatingmaterials of the group consisting of sodium nitrite, potassium nitrite,calcium nitrite and barium nitrite and mixtures thereof in the ratio ofabout 1 to 4 to about 4 to 1 parts by weight of the aeration agent.Sodium bicarbonate and sodium nitrite in preparation by weight of aboutto l to about 1 to 2 are generally used in substantially equalproportion and are preferred. The term aeration agent as used hereinmeans an agent which causes the explosive composition to be combinedwith or charged with gas. The term maximum specific gravity as usedherein means the specific gravity of the aqueous slurry explosivecomposition exclusive of gas.

It has been found that the aeration agent of the present invention maybe incorporated into gelled aqueous slurry compositions in an amount offrom about 0.01 to about 1.00% and preferably from about 0.02 to about0.50% by weight of the slurry composition. Within the range of theaforementioned amounts are compositions having specific gravitieslowered to between about 30 to of maximum for those containingnon-explosive ingredients and lowered to between about 30 and f maximumtor those containing explosive sensitizing agents. Furthermore. it willbe appreciated that benefits from the invention inure when the aerationagent of the present invention is utilized with gelled aqueous slurrycompositions containing explosive sensitizers, such as smokeless powder.TNT. RDX, PETN, HBX, and the like. as Well as aqueous slurrycompositions in which all ingredients per it? are non-explosive.Additionally, it will be appreciated that benefits from the inventioninure when the aeration agent of the present invention is ultilized Withgelled aqueous slurry compositions containing non-explosive energizersother than aluminum and silicon or combined therewith, such as, calciumsilicide, calcium boride, silicon carbide, ferrosilicon, magnesiumalloy, and the like.

Suitable thickeners include cross-linkable materials, such as,carboxymethylcellulose and guar gum to form the gelled aqueous slurryexplosive. Guar gum present in cross-linked form is preferred inconjunction with the present invention to impart a plastic but easilydeformable consistency for retaining the dispersed gas ingredients overprolonged periods as packaged or placed into boreholes.

It will be seen, therefore, that this invention may be carried out bythe use of various modification and changes without departing from itsspirit and scope, with only such limitations placed thereon as areimposed by the appended claims.

What we claim and desire to protect by Letters Patent are:

1. An improved explosive composition comprising at least one fast gasgenerating material of the group consisting of sodium bicarbonate,potassium bicarbonate, sodium carbonate and potassium carbonate and atleast one slow gas generating material of the group consisting of sodiumnitrite, potassium nitrite, calcium nitrite and barium nitrite dispersedin a gelled aqueous slurry explosive composition of the inorganicoxidizer salt type in which said gas generating materials cause saidcomposition to be charged with gas in an amount sufiicient for adjustingand maintaining a predetermined specific gravity for said composition.

2. The composition according to claim 1 wherein the ratio of the fastgenerating material to the slow gas generating material is from about 1to 4 to about 4 to 1 parts by weight.

3. The composition according to claim 1 wherein the ratio of the fastgas generating material to the slow gas generating material is fromabout 1 to 2 to about 2 to 1 parts by weight.

4. The composition according to claim 3 wherein the rapidly released gasof the fast gas generating material is substantially water soluble andthe slowly released gas of the slow gas generating material issubstantially Water insoluble.

5. The composition according to claim 4 wherein the fast gas generatingmaterial is sodium bicarbonate and the slow gas generating material issodium nitrite in substantially equal proportion by weight.

References Cited UNITED STATES PATENTS 11/1966 Ferguson et al. 149211/1966 Swisstack 149-42 X

